The highly significant isomers among the following compounds are
A. Methane B. Propane
C. Butane D. Hexane

Options

A. A and B
B. A and D
C. B and C
D. C and D

Explanation

To determine the highly significant isomers among the given compounds (Methane, Propane, Butane, and Hexane), we need to analyze each compound based on the number of carbon atoms and the possibility of structural isomers.

### Step-by-Step Solution:

1. **Understanding Isomers**:
- Isomers are compounds that have the same molecular formula but different structural formulas. This means they have the same number of atoms of each element but are arranged differently.

2. **Analyzing Methane (CH4)**:
- Methane has only one carbon atom. Since isomers require at least 3 carbon atoms to exist, methane cannot have any isomers.
- **Conclusion**: Methane has 0 isomers.

3. **Analyzing Propane (C3H8)**:
- Propane consists of 3 carbon atoms. Similar to methane, it does not have enough carbon atoms to form isomers.
- **Conclusion**: Propane has 0 isomers.

4. **Analyzing Butane (C4H10)**:
- Butane has 4 carbon atoms. It can exist in two structural forms:
1. **n-Butane**: CH3-CH2-CH2-CH3 (a straight chain)
2. **Isobutane**: (CH3)2CH-CH3 (a branched chain)
- **Conclusion**: Butane has 2 isomers.

5. **Analyzing Hexane (C6H14)**:
- Hexane has 6 carbon atoms and can exist in several structural forms. The possible isomers of hexane include:
1. **n-Hexane**: CH3-CH2-CH2-CH2-CH2-CH3 (a straight chain)
2. **2-Methylpentane**: CH3-CH(CH3)-CH2-CH2-CH3 (one branch)
3. **3-Methylpentane**: CH3-CH2-CH(CH3)-CH2-CH3 (another branch)
4. **2,2-Dimethylbutane**: (CH3)2C(CH3)CH2-CH3 (two branches)
5. **2,3-Dimethylbutane**: CH3-CH(CH3)-CH(CH3)-CH3 (two branches)
6. **3,3-Dimethylbutane**: (CH3)3C-CH2-CH3 (three branches)
- **Conclusion**: Hexane has 5 isomers.

### Final Conclusion:
- Methane: 0 isomers
- Propane: 0 isomers
- Butane: 2 isomers
- Hexane: 5 isomers

Thus, the highly significant isomers among the given compounds are **Butane and Hexane**.